Unless you want to add another zero to your budget i wouldn't even consider it a budget. i also wouldn't bother messing around with much performance stuff, that 6.0 will swallow that thousand bucks in one hiccup.

Other than what he said i would get an electronic gauge (insight or scangauge), exhaust and then check fuel pressure, batteries, ficm etc. and make sure you have enough money to keep up on your preventative maintenance.

It sucks but your looking at well north of $1,000 in parts to make the motor capable of handling its stock tune.
Ford rly f'd up by putting a hot tune on that motor from the factory.

Save another $500ish and then buy
EGR Delete (Sinister Diesel IMO)
ARP head studs
OEM head gaskets
OEM oil cooler
All the other gaskets youll need to replace.
Coolant filtration system
Search "Sinister total 6.0 solution" and buy all that shit except skip the sinister head gaskets and get OEM Ford Gaskets.
Find a reputable 6.0 guy (unless you Can tackle the job yourself)

I just put $4500 into my 6.0 by having a diesel mech do this stuff (and a few other necessities) cuz i dont have the facility, tools and knowledge to do it.

Now im confident the top can handle its stock tune on up to about 450 HP

But if your crazy lucky you may have a 6.0 block that was clean and the oil cooler will hold up for a while but the egr systems are all garbage.

As a 6.0 owner that has been to the end of the internet researching this shit if you own a 6.0 and start it, it needs these mods. It sucks but its true.

FWIW i was at 108,000 miles before mine started blowing coolant, by 109,000 all hell was breaking loose.

End of rant.

But if i didnt care about the truck i would take that grand and get an SCT live wire, get ahold of The TSD Super panty dropper file and have a few miles of fun before the head gaskets let go. Lols